Top 50 MCQs for CBSE Class 12 Biology Half Yearly Exam 2028

This article offers a curated selection of crucial Multiple Choice Questions (MCQs) for CBSE Class 12th Biology Mid Term Exam, specifically designed to aid students in their Class 12th biology half-yearly examination preparation. These MCQs have been meticulously crafted by a team of subject matter experts, ensuring accuracy, relevance, and alignment with the latest CBSE syllabus and examination pattern. 

The questions cover a wide range of topics within the CBSE Class 12th Biology curriculum, providing a thorough review of key concepts and important details that are frequently tested in examinations. By practicing these expert-designed MCQs, students can effectively assess their understanding, identify areas requiring further study, and enhance their problem-solving skills, ultimately boosting their confidence for the upcoming half-yearly Biology exam.

CBSE Class 12th Biology Half Yearly Important MCQs

1.Which of the following statements is TRUE about the gamete mother cells in human beings?

A. They are diploid and undergo mitotic divisions.

B. They are diploid and undergo meiotic divisions.

C. They are haploid and undergo meiotic divisions.

D. They are haploid and do not undergo cell division. 

2.Two statements are given - one labelled Assertion (A) and the other labelled Reason (R). Assertion (A): Organisms like Amoeba produce multiple minute amoebae through sporulation. Reason (R): Sporulation involves meiotic division to produce multiple cells from one cell. Which of the following is CORRECT?

A. Both A and R are true, but R is not the correct explanation of the assertion.
B. Both A and R are true, and R is the correct explanation of the assertion.

C. A is true, but R is false.

D. A is false, but R is true

3.During apomictic seed formation, there is no reduction division and the gametes (both egg cell and the pollen/sperm cells) are diploid. What is the ploidy of the endosperm formed through apomixis? A. 2n B. 3n C. 4n D. 6n 

4.Which of the following is TRUE for a flower giving rise to a false fruit in apple?

A. The ovary is infertile.

B. The ovary does not undergo fertilisation.

C. The thalamus undergoes fertilisation.

D. The thalamus forms a part of the fruit.

5.Which of these cells of the human male reproductive system is haploid?

A. Spermatid

B. Sertoli cell

C. Leydig cell

D. Spermatogonium

6.Globozoospermia is a condition where sperms have a characteristic round head lacking the acrosome. Which of the following functions will a sperm NOT be able to do because of the above condition?

A. Enter the cervix

B. Penetrate the ovum 

C. Leave the ejaculatory duct

D. Swim to the Fallopian tu

7.Which of these hormones would be detected in both a pregnant female and a female who is not pregnant?

A. Relaxin

B. Prolactin

C. Progesterone

D. Human chorionic gonadotropin

8.Some events of pregnancy in humans are written below in a sequence. (i) complete development of foetus (ii) uterine contraction (iii) dilation of cervix (iv) delivery of the baby (v) lactation Between which of the following events does the shedding of the placenta happen?

A. (i) and (ii)

B. (ii) and (iii)

C. (iii) and (iv)

D. (iv) and (v)

9.Which of the following methods of assisted reproductive technologies (ART) can be a more viable process of pregnancy in a woman after menopause?

A. Gamete intra fallopian transfer

B. Zygote intra fallopian transfer

C. Artificial insemination

D. Pregnancy is not possible after menopause

10.A group of students are trying to replicate the famous Miller-Urey experiment using a different set of molecules compared to those employed in the original study. Their experiment will be deemed supportive and aligning with the Miller-Urey experiment solely on the condition that the molecular weight of -

A. reactants ≥ products

B. reactants < products

C. reactants = products

D. reactants > products

11.Billions of years ago, when Earth had a reducing atmosphere containing methane and ammonia along with high temperatures, the organisms that came to existence would have been -

A. aerobic and chemo-autotrophic

B. anaerobic and chemo-heterotrophic

C. aerobic and chemo-heterotrophic

D. anaerobic and chemo-autotrophic

12.Which of the following phenomena significantly contributes to speciation? P) Natural Selection Q) Genetic Drift R) Gene flow S) Geographic Isolation T) Stabilizing Selection

A. only Q and S

B. only R and T

C. only P, Q and S

D. only Q, R and T

13.The Hardy-Weinberg principle is a foundational principle for understanding population genetics with several assumptions. Which of the following is NOT an assumption of this principle?

A. Random mating

B. Emigration of species

C. Large population size

D. Non-occurrence of mutations

14.Enzyme-linked immunosorbent assay (ELISA) is used for testing if the patient is suffering from AIDS or not. In this test, the enzyme-linked antibodies bind to __________ in the blood sample and help in their detection. Fill in the blank -

A. HIV DNA

B. HIV RNA

C. HIV antibody or antigen

D. HIV reverse transcriptase

15.As a part of increasing immunity against COVID-19, a small part of the virus is administered to people as a vaccine. Which of the following types of immunity is the above an example of?

A. Naturally acquired active immunity

B. Naturally acquired passive immunity

C. Artificially acquired active immunity

D. Artificially acquired passive immunity

16.Complete DiGeorge Syndrome is when the child is born without the thymus. Which of the following processes is likely to be impaired in such individuals?

A. Red blood cell production

B. Thyroxine production

C. Antibody production

D. Antigen production

17. It is caused by a fungi. - An individual infected with it shows dry scaly lesions on various body parts. Which of the following disease do these hints refer to?

A. Ringworm

B. Filariasis

C. Amoebiasis

D. Ascariasis 

18.Which of these infections is NOT caused by a worm?

A. Filariasis

B. Ringworm

C. Round worm

D. Elephantiasis

19.Two statements are given below - one labelled Assertion (A) and the other labelled Reason (R).

Assertion (A): Single cell proteins have the potential to meet the growing demand for food and eliminate hunger.

Reasoning (R): The yield of proteins from conventional agriculture is more than the yield of proteins from microbes. Which of the following is correct?

A. Both A and R are true, and R is a correct explanation for A.

B. Both A and R are true, and R is not a correct explanation for A.

C. A is true, but R is false.

D. A is false, but R is true

20.Industrial production of which of these products can be negatively affected by the presence of Saccharomyces cerevisiae?

A. Beer

B. Wine

C. Fruit juice

D. Wheat bread

21. A pharmaceutical industry aims to develop a chemical that can induce immune system modulation in patients with autoimmune diseases and help in alleviating symptoms. Which of the following microbes should they consider utilizing?

A. Aspergillus niger

B. Staphylococcus aureus

C. Trichoderma polysporum

D. Saccharomyces cerevisiae

22.An industry aims to transition from a small-scale experimental bioreactor to a large bioreactor for the production of an enzyme. Which of the following parameters would be CONSTANT during the scaling-up process? P) pH profile Q) Reactor capacity

R) Volume of inoculum S) Temperature profile T) Initial nutrient concentration

A. Only P, R and S

B. Only P, Q and R

C. Only Q, T and R

D. Only P, S and T

23.A pharmaceutical company is working on a drug based on statin and is searching for appropriate candidates for clinical tests so as to evaluate its safety, efficacy, and potential therapeutic benefits in a controlled and monitored setting and obtain potential regulatory approval. Which of the following would serve as suitable candidates to obtain samples? A. A professional swimmer.

B. A person who recently recovered from dengue.

C. A gym trainer who consumes protein in higher quantities.

D. A person who consumes saturated fats in higher quantities.

24.Transgenic mice are being developed to replace the use of monkeys for laboratory testing of vaccines or drugs meant for humans. Which of the following is/are POSSIBLE reasons for this move? P) Mice and humans have similar physiology. Q) The reproduction rate is faster in mice.

A. only P

B. only Q

C. both P and Q

D. neither P nor Q

25.In the sequence of producing recombinant MAP2 protein, Meera had to perform gel electrophoresis immediately after a PCR (Polymerase Chain Reaction). What could have been Meera's primary goal for performing gel electrophoresis?

A. Separating the positively and negatively charged MAP2 DNA fragments.

B. Separating the cloned MAP2 DNA from other DNA fragments.

C. Separating recombinant MAP2 protein from other proteins. D. Separating cloned MAP2 DNA from MAP2 protein.

26.Two statements are given below - one labelled Assertion (A) and the other labelled Reason (R).

Assertion (A): The energy utilised by an organism for growth is not transferred to the next trophic level.

Reason (R): Growth causes an increase in biomass. Which of the following is correct? A. Both A and R are true, and R is the correct explanation for A. B. Both A and R are true, but R is not the correct explanation for

A. C. A is true, but R is false.

D. A is false, but R is true

27.If X is the amount of energy produced by the producers, which of the following is the correct amount of energy received by humans from the producers in a food web?

A. only 10%

B. either 10% or 1%

C. either 10%, 1% or 0.1%

D. Humans are not part of a food web.

28.If the energy produced by the producers of a food web is 20,810 kcal, what is the minimum amount of energy that will be available to snakes in this food web?

A. 383 kcal

B. 2081 kcal

C. 10000 kcal

D. Cannot say without knowing the level that is occupied by snakes in this chain.

29.A carbon sink is any environment that can store carbon and remove it from the atmosphere. Which of the following will lead to a DECLINE in carbon sink?

A. Deforestation

B. Population growth

C. Burning of fossil fuels

D. Increase in industrial activity

30.Which of the following is/are example/s of biodiversity?

(i) Animals and emigrants in an area.

(ii) Microorganisms present in the intestine of an organism.

(iii) Cell from the same tissue in different organisms.

A. only (i)

B. only (ii)

C. only (ii) and (iii)

D. all - (i), (ii) and (iii)

31.What happens to the BOD of a water body with REMOVAL of effluents from it?

A. Increases

B. Decreases

C. Remains the same

D. Increases and then stagnates

32.Which of the following statements are CORRECT about the process of eutrophication? (P) Increase in nutrient levels (Q) Increase in water clarity (R) Decrease in dissolved oxygen (S) Decrease in penetration of sunlight into water (T) Decrease in the growth of algae and aquatic plants

A. Only (P) and (R)

B. Only (P), (R), and (S)

C. Only (Q), (R), and (T)

D. All - (P), (Q), (R), (S), and (T)

33.A mass of nutritive material outside the embryo sac is called _____

A. Protoplasm

B. Pericarp

C. Ectoderm

D. Perisperm

34.The male reproductive parts of a flower, the stamens, are collectively known as

A. Androecium

B. Filament

C. Anther

D. Gynoecium

35.Which of the following statements is TRUE about the gamete mother cells in human beings?

A. They are diploid and undergo mitotic divisions.

B. They are diploid and undergo meiotic divisions.

C. They are haploid and undergo meiotic divisions.

D. They are haploid and do not undergo cell division. 

36.Which of the following population definitely has/have a greater chance of survival in a stable habitat?

P) Those with greater variation.

Q) Those with a greater number of individuals expressing the dominant trait.

R) Those living in environmental conditions that provide an advantage to the species.

A. Only Q

B. Only R

C. Only P and R

D. All - P, Q and R

37.Given below is a list of some statements about reproduction in organisms. P) Reproduction must involve the fusion of gametes. Q) Heterogametes can be formed from two parents. R) Reproduction always creates genetically different offspring. Which among the above is/are TRUE?

A. Only P

B. Only Q

C. Only P and Q

38.Polymerase chain reaction (PCR) mimics which of the following natural processes?

A. ligation

B. translation

C. replication

D. transformation

39.Which of the following correctly states the purpose of steam in a bioprocessor?

A. helps organisms grow faster

B. adds to the water content

C. maintains sterility

D. (Steam is not required in a bio-processing unit.)

40.What would be the colour of the colonies formed by variant P?

A. only blue colonies

B. only white colonies

C. a mix of blue and white colonies

D. (They will not form any colonies.)

41.In which of the following natural processes is recombinant DNA made?

A. prophase in mitosis

B. prophase 1 in meiosis

C. prophase 2 in meiosis

D. (Recombinant DNA cannot be made naturally)

42.Immuno-suppressants are administered to patients post-organ transplantation and also to those suffering from auto-immune disorders. In which of the following ways are immuno-suppressants helpful?

A. They trigger allergic response.

B. They eliminate unhealthy tissues.

C. They control the cell-mediated response.

D. They differentiate between self and non-self parts of the body.

43.Trees in some regions have very thin barks, broad leaves placed at different angles to allow them to capture adequate sunlight and leaves with pointed tips that allow water to run off easily. In which biome are such trees likely to be found?

A. arctic

B. desert

C. coastal

D. rainforests

44.The larvae of insects such as the African midge inhabit temporary pools in hollows of rocks when water evaporates in their arid environment. These larvae revive when immersed in water even after a few years. Which response to abiotic stress does the statement depict?

A. regulation

B. migration

C. suspension

D. conformation 

45.In which of the following process would genetic variation occur? P) mutation in liver cells Q) development of a zygote to an embryo R) gene flow from one population to another

A. only P

B. only Q

C. only P and Q

D. only P and R

46.In mice, brown fur is dominant and white fur is recessive. A biologist crossed a brown fur male with a white fur female and obtained two brown fur and two white fur offspring. Which of the following statementsis MOST likely to be true?

A. Both parents are heterozygous.

B. Only the male parent is homozygous.

C. Only the male parent is heterozygous.

D. Only the female parent is heterozygous

47.In a cross between pea plants having round green seeds (RRGG) and wrinkled yellow seeds(rrgg), what percentage of eggs will carry both the round and green alleles for the F2 generation?

A. 9%

B. 93%

C. 64% 

D. 25%

48.Which ofthe following phenomenon is/are exhibited by alleles coding for kernel colour in wheat? P) co-dominance Q) incomplete dominance R) polygenic inheritance

A. only P

B. only R

C. only P and R

D. only Q and R

49.Which of the following is an indicator of a reproductively unhealthy society?

A.increase in infant mortality rate

B.decline in maternal mortality rate

C.widespread awareness of contraceptive methods

D.detection and cure ofsexually transmitted diseases

50.Amniocentesis is a medical procedure where some of the amniotic fluid of the developing foetus is drawn to analyse the foetal cells and dissolved substances. It was banned in India around 1994 under the Pre-Conception and Prenatal Diagnostic Techniques Act in order to stop female foeticides. Which of the following highlight the importance of amniocentesis despite the ban?

A.identification of a decline in sex ratio

B.prevention of sexually transmitted diseases

C.determination of biological sex of the unborn baby

D.detection of genetic disorders

CBSE Class 12th Biology Half Yearly Important MCQs - Answer Key

Also Check - CBSE Class 12 Biology Half Year Sample Paper